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    <meta name="description" content="栈的应用一、括号匹配二、表达式求值1、中缀表达式即正常的表达式，需要使用括号标明计算顺序，可由树的中序遍历得到 例如： ((1+2&#x2F;2)*3-4&#x2F;(1+2-4)*2) 2、后缀表达式（逆波兰表达式）不需要括号，可由树的后序遍历得到 例如： 1 2 2 &#x2F; + 3 * 4 1 2 + 4 - &#x2F; 2 *- 3、前缀表达式（波兰表达式）不需要括号，可由树的前序遍历得到 例如： - * + 1 &#x2F; 2">
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<meta property="og:description" content="栈的应用一、括号匹配二、表达式求值1、中缀表达式即正常的表达式，需要使用括号标明计算顺序，可由树的中序遍历得到 例如： ((1+2&#x2F;2)*3-4&#x2F;(1+2-4)*2) 2、后缀表达式（逆波兰表达式）不需要括号，可由树的后序遍历得到 例如： 1 2 2 &#x2F; + 3 * 4 1 2 + 4 - &#x2F; 2 *- 3、前缀表达式（波兰表达式）不需要括号，可由树的前序遍历得到 例如： - * + 1 &#x2F; 2">
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            <h1 style="display: none">栈的应用</h1>
            
            
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                <h2 id="栈的应用"><a href="#栈的应用" class="headerlink" title="栈的应用"></a>栈的应用</h2><h3 id="一、括号匹配"><a href="#一、括号匹配" class="headerlink" title="一、括号匹配"></a>一、括号匹配</h3><h3 id="二、表达式求值"><a href="#二、表达式求值" class="headerlink" title="二、表达式求值"></a>二、表达式求值</h3><h4 id="1、中缀表达式"><a href="#1、中缀表达式" class="headerlink" title="1、中缀表达式"></a>1、中缀表达式</h4><p>即正常的表达式，需要使用括号标明计算顺序，可由树的中序遍历得到</p>
<p>例如：</p>
<p><code>((1+2/2)*3-4/(1+2-4)*2)</code></p>
<h4 id="2、后缀表达式（逆波兰表达式）"><a href="#2、后缀表达式（逆波兰表达式）" class="headerlink" title="2、后缀表达式（逆波兰表达式）"></a>2、后缀表达式（逆波兰表达式）</h4><p>不需要括号，可由树的后序遍历得到</p>
<p>例如：</p>
<p><code>1 2 2 / + 3 * 4 1 2 + 4 - / 2 *-</code></p>
<h4 id="3、前缀表达式（波兰表达式）"><a href="#3、前缀表达式（波兰表达式）" class="headerlink" title="3、前缀表达式（波兰表达式）"></a>3、前缀表达式（波兰表达式）</h4><p>不需要括号，可由树的前序遍历得到</p>
<p>例如：</p>
<p><code>- * + 1 / 2 2 3 / 4 * + 1 - 2 4 2</code></p>
<blockquote>
<p>中缀表达式转化成前、后缀表达式后，操作数的前后顺序并没有发生改变。</p>
<p>对于后缀表达式，当一个运算符前边有俩个连续的数（如：ab-），就可以进行运算 a-b</p>
<p>对于前缀表达式，当一个运算符后边有俩个连续的数（如：-ab），就可以进行运算 a-b</p>
</blockquote>
<h4 id="表达式的转换"><a href="#表达式的转换" class="headerlink" title="表达式的转换"></a>表达式的转换</h4><h5 id="中缀转后缀"><a href="#中缀转后缀" class="headerlink" title="中缀转后缀"></a>中缀转后缀</h5><p>1、手算方法</p>
<p>按照优先级依次处理某个运算符，将其局部转化为后缀表达式，并将转化后的局部表达式看作是一个操作数，然后重复当前步骤。  直到所有部分都转化为后缀表达式的形式</p>
<p>如果遇到遇到俩个运算符优先级相等，应优先处理左边的运算符，即：遵循<strong>左右先</strong>原则</p>
<p>例如：而对于<code>1+2-3</code>这样的式子,优先处理左边的加号得到<code>1 2 +</code>，再将<code>1 2 +</code>看作操作数，即：a-3，转化后得<code>a 3 -</code>,即<code>1 2 + 3 -</code></p>
<p>2、代码</p>
<figure class="highlight cpp"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br></pre></td><td class="code"><pre><code class="hljs cpp"><span class="hljs-meta">#<span class="hljs-keyword">include</span><span class="hljs-string">&lt;string&gt;</span></span><br><span class="hljs-meta">#<span class="hljs-keyword">include</span><span class="hljs-string">&lt;iostream&gt;</span></span><br><span class="hljs-meta">#<span class="hljs-keyword">include</span><span class="hljs-string">&lt;stack&gt;</span> </span><br><span class="hljs-meta">#<span class="hljs-keyword">include</span><span class="hljs-string">&lt;map&gt;</span></span><br><br><span class="hljs-keyword">using</span> <span class="hljs-keyword">namespace</span> std;<br><br><span class="hljs-function"><span class="hljs-type">int</span> <span class="hljs-title">main</span><span class="hljs-params">()</span></span>&#123;<br>	stack&lt;<span class="hljs-type">char</span>&gt; stk;<br>	map&lt;<span class="hljs-type">char</span>,<span class="hljs-type">int</span>&gt; mp = &#123;&#123;<span class="hljs-string">&#x27;+&#x27;</span>,<span class="hljs-number">1</span>&#125;,&#123;<span class="hljs-string">&#x27;-&#x27;</span>,<span class="hljs-number">1</span>&#125;,&#123;<span class="hljs-string">&#x27;*&#x27;</span>,<span class="hljs-number">2</span>&#125;,&#123;<span class="hljs-string">&#x27;/&#x27;</span>,<span class="hljs-number">2</span>&#125;&#125;;<br>	string s,res;<br>	<span class="hljs-built_in">getline</span>(cin,s);<br>	<span class="hljs-comment">//遍历中缀表达式</span><br>	<span class="hljs-keyword">for</span>(<span class="hljs-type">int</span> i = <span class="hljs-number">0</span>;i&lt;s.<span class="hljs-built_in">size</span>();i++)&#123;<br>		<span class="hljs-type">char</span> c = s.<span class="hljs-built_in">at</span>(i);<br>		<span class="hljs-keyword">if</span>(c == <span class="hljs-string">&#x27;(&#x27;</span>)&#123;<br>			stk.<span class="hljs-built_in">push</span>(c);<br>		&#125;<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(c ==<span class="hljs-string">&#x27;)&#x27;</span>)&#123;<br>			<span class="hljs-keyword">while</span>(stk.<span class="hljs-built_in">top</span>()!=<span class="hljs-string">&#x27;(&#x27;</span>)&#123;<br>				res.<span class="hljs-built_in">push_back</span>(stk.<span class="hljs-built_in">top</span>());<br>				res.<span class="hljs-built_in">push_back</span>(<span class="hljs-string">&#x27; &#x27;</span>);<br>				stk.<span class="hljs-built_in">pop</span>();<br>			&#125;<br>			stk.<span class="hljs-built_in">pop</span>();<br>		&#125;<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(c&gt;=<span class="hljs-string">&#x27;0&#x27;</span>&amp;&amp;c&lt;=<span class="hljs-string">&#x27;9&#x27;</span>)&#123;<br>			res.<span class="hljs-built_in">push_back</span>(c);<br>			res.<span class="hljs-built_in">push_back</span>(<span class="hljs-string">&#x27; &#x27;</span>);<br>		&#125;<span class="hljs-keyword">else</span>&#123;<br>			<span class="hljs-keyword">if</span>(stk.<span class="hljs-built_in">empty</span>()||stk.<span class="hljs-built_in">top</span>() == <span class="hljs-string">&#x27;(&#x27;</span>)&#123;<br>				stk.<span class="hljs-built_in">push</span>(c);<br>				res.<span class="hljs-built_in">push_back</span>(<span class="hljs-string">&#x27; &#x27;</span>);	<br>			&#125;<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(mp[c]&lt;=mp[stk.<span class="hljs-built_in">top</span>()])&#123;<span class="hljs-comment">//下一个运算符的优先级小于等于当前栈顶运算符优先级 </span><br>				res.<span class="hljs-built_in">push_back</span>(stk.<span class="hljs-built_in">top</span>());<br>				res.<span class="hljs-built_in">push_back</span>(<span class="hljs-string">&#x27; &#x27;</span>);<br>				stk.<span class="hljs-built_in">pop</span>();<br>				stk.<span class="hljs-built_in">push</span>(c);<br>			&#125;<span class="hljs-keyword">else</span>&#123;<br>				stk.<span class="hljs-built_in">push</span>(c);<br>				res.<span class="hljs-built_in">push_back</span>(<span class="hljs-string">&#x27; &#x27;</span>);<br>			&#125;<br>		&#125;<br>	&#125;<br>    <span class="hljs-comment">//处理栈中剩余的运算符</span><br>	<span class="hljs-keyword">while</span>(!stk.<span class="hljs-built_in">empty</span>())&#123;<br>		res.<span class="hljs-built_in">push_back</span>(stk.<span class="hljs-built_in">top</span>());<br>		res.<span class="hljs-built_in">push_back</span>(<span class="hljs-string">&#x27; &#x27;</span>);<br>		stk.<span class="hljs-built_in">pop</span>();<br>	&#125;<br>	cout&lt;&lt;res;<br>&#125; <br></code></pre></td></tr></table></figure>



<h5 id="中缀转前缀"><a href="#中缀转前缀" class="headerlink" title="中缀转前缀"></a>中缀转前缀</h5><p>1、手算方法 </p>
<p>方法同上，不同的是中缀转前缀应遵循<strong>右优先</strong>原则以确定运算符的运算次序</p>
<p>2、代码</p>
<h5 id="后缀、前缀转中缀"><a href="#后缀、前缀转中缀" class="headerlink" title="后缀、前缀转中缀"></a>后缀、前缀转中缀</h5><h4 id="前、后缀表达式求值"><a href="#前、后缀表达式求值" class="headerlink" title="前、后缀表达式求值"></a>前、后缀表达式求值</h4><h4 id="表达式求值"><a href="#表达式求值" class="headerlink" title="表达式求值"></a>表达式求值</h4><figure class="highlight cpp"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br><span class="line">54</span><br><span class="line">55</span><br><span class="line">56</span><br><span class="line">57</span><br><span class="line">58</span><br><span class="line">59</span><br><span class="line">60</span><br><span class="line">61</span><br><span class="line">62</span><br><span class="line">63</span><br><span class="line">64</span><br><span class="line">65</span><br><span class="line">66</span><br><span class="line">67</span><br><span class="line">68</span><br><span class="line">69</span><br><span class="line">70</span><br><span class="line">71</span><br><span class="line">72</span><br><span class="line">73</span><br><span class="line">74</span><br><span class="line">75</span><br><span class="line">76</span><br><span class="line">77</span><br><span class="line">78</span><br><span class="line">79</span><br><span class="line">80</span><br><span class="line">81</span><br><span class="line">82</span><br><span class="line">83</span><br><span class="line">84</span><br><span class="line">85</span><br><span class="line">86</span><br><span class="line">87</span><br><span class="line">88</span><br><span class="line">89</span><br><span class="line">90</span><br><span class="line">91</span><br><span class="line">92</span><br><span class="line">93</span><br><span class="line">94</span><br><span class="line">95</span><br><span class="line">96</span><br><span class="line">97</span><br><span class="line">98</span><br><span class="line">99</span><br><span class="line">100</span><br><span class="line">101</span><br><span class="line">102</span><br><span class="line">103</span><br><span class="line">104</span><br><span class="line">105</span><br><span class="line">106</span><br><span class="line">107</span><br><span class="line">108</span><br><span class="line">109</span><br><span class="line">110</span><br><span class="line">111</span><br><span class="line">112</span><br><span class="line">113</span><br><span class="line">114</span><br><span class="line">115</span><br><span class="line">116</span><br><span class="line">117</span><br><span class="line">118</span><br><span class="line">119</span><br><span class="line">120</span><br><span class="line">121</span><br><span class="line">122</span><br><span class="line">123</span><br></pre></td><td class="code"><pre><code class="hljs cpp"><span class="hljs-meta">#<span class="hljs-keyword">include</span><span class="hljs-string">&lt;string&gt;</span></span><br><span class="hljs-meta">#<span class="hljs-keyword">include</span><span class="hljs-string">&lt;iostream&gt;</span></span><br><span class="hljs-meta">#<span class="hljs-keyword">include</span><span class="hljs-string">&lt;stack&gt;</span></span><br><span class="hljs-meta">#<span class="hljs-keyword">include</span><span class="hljs-string">&lt;map&gt;</span></span><br><br><br><span class="hljs-keyword">using</span> <span class="hljs-keyword">namespace</span> std;<br><br>stack&lt;<span class="hljs-type">int</span>&gt; stk_num;<br>stack&lt;<span class="hljs-type">char</span>&gt; stk_op;<br><span class="hljs-comment">//优先级 </span><br>map&lt;<span class="hljs-type">char</span>,<span class="hljs-type">int</span>&gt; mp = &#123;&#123;<span class="hljs-string">&#x27;+&#x27;</span>,<span class="hljs-number">1</span>&#125;,&#123;<span class="hljs-string">&#x27;-&#x27;</span>,<span class="hljs-number">1</span>&#125;,&#123;<span class="hljs-string">&#x27;*&#x27;</span>,<span class="hljs-number">2</span>&#125;,&#123;<span class="hljs-string">&#x27;/&#x27;</span>,<span class="hljs-number">2</span>&#125;&#125;;<br><br><span class="hljs-comment">//计算 a op b </span><br><span class="hljs-function"><span class="hljs-type">int</span> <span class="hljs-title">f</span><span class="hljs-params">(<span class="hljs-type">int</span> a,<span class="hljs-type">int</span> b,<span class="hljs-type">char</span> op)</span></span>&#123;<br>	<span class="hljs-keyword">if</span>(op ==<span class="hljs-string">&#x27;-&#x27;</span>)&#123;<br>		<span class="hljs-keyword">return</span> a-b;<br>	&#125;<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(op ==<span class="hljs-string">&#x27;+&#x27;</span>)&#123;<br>		<span class="hljs-keyword">return</span> a+b;<br>	&#125;<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(op ==<span class="hljs-string">&#x27;*&#x27;</span>)&#123;<br>		<span class="hljs-keyword">return</span> a*b;<br>	&#125;<span class="hljs-keyword">else</span>&#123;<br>		<span class="hljs-keyword">return</span> a/b;<br>	&#125;<br>&#125;<br><br><span class="hljs-function"><span class="hljs-type">int</span> <span class="hljs-title">calculate</span><span class="hljs-params">(string s)</span></span>&#123;<br>	<span class="hljs-comment">//遍历表达式</span><br>	<span class="hljs-type">int</span> i = <span class="hljs-number">0</span>;<br>	<span class="hljs-type">int</span> a;<span class="hljs-comment">//左操作数</span><br>	<span class="hljs-type">int</span> b;<span class="hljs-comment">//右操作数</span><br>	<span class="hljs-type">char</span> op;<span class="hljs-comment">//运算符 </span><br>	<span class="hljs-type">int</span> res;<span class="hljs-comment">//运算结果 </span><br>	<span class="hljs-keyword">while</span>(i&lt;s.<span class="hljs-built_in">size</span>())&#123;<br>		<span class="hljs-type">char</span> c = s.<span class="hljs-built_in">at</span>(i);<br>		<span class="hljs-keyword">if</span>(c == <span class="hljs-string">&#x27;(&#x27;</span>)&#123;<br>			stk_op.<span class="hljs-built_in">push</span>(c);<br>			i++; <br>		&#125;<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(c == <span class="hljs-string">&#x27;)&#x27;</span>)&#123;<br>			<span class="hljs-keyword">while</span>(stk_op.<span class="hljs-built_in">top</span>() != <span class="hljs-string">&#x27;(&#x27;</span>)&#123;<br>				<span class="hljs-comment">//取出操作数，先取出来的是右操作数 </span><br>				b = stk_num.<span class="hljs-built_in">top</span>();<br>				stk_num.<span class="hljs-built_in">pop</span>();<br>				a = stk_num.<span class="hljs-built_in">top</span>();<br>				stk_num.<span class="hljs-built_in">pop</span>();<br>				<span class="hljs-comment">//取出运算符</span><br>				op = stk_op.<span class="hljs-built_in">top</span>();<br>				stk_op.<span class="hljs-built_in">pop</span>();<br>				<span class="hljs-comment">//运算</span><br>				res = <span class="hljs-built_in">f</span>(a,b,op);<br>				<span class="hljs-comment">//结果入栈 </span><br>				stk_num.<span class="hljs-built_in">push</span>(res); <br>			&#125;<br>			stk_op.<span class="hljs-built_in">pop</span>();<span class="hljs-comment">//将&#x27;(&#x27;出栈 </span><br>			i++;<br>		&#125;<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(c&lt;=<span class="hljs-string">&#x27;9&#x27;</span>&amp;&amp;c&gt;=<span class="hljs-string">&#x27;0&#x27;</span>)&#123;<br>			<span class="hljs-comment">//将数字从字符串中取出，并入栈</span><br>			string num;<br>			<span class="hljs-keyword">while</span>(i&lt;s.<span class="hljs-built_in">size</span>()&amp;&amp;s.<span class="hljs-built_in">at</span>(i)&lt;=<span class="hljs-string">&#x27;9&#x27;</span>&amp;&amp;s.<span class="hljs-built_in">at</span>(i)&gt;=<span class="hljs-string">&#x27;0&#x27;</span>)&#123;<br>				num.<span class="hljs-built_in">push_back</span>(s.<span class="hljs-built_in">at</span>(i));<br>				i++;<br>			&#125;<br>			stk_num.<span class="hljs-built_in">push</span>(<span class="hljs-built_in">stoi</span>(num)); <br>		&#125;<span class="hljs-keyword">else</span>&#123;<span class="hljs-comment">//遇到操作符 </span><br>			<span class="hljs-keyword">if</span>(stk_op.<span class="hljs-built_in">empty</span>())&#123;<br>				stk_op.<span class="hljs-built_in">push</span>(c);<br>			&#125;<span class="hljs-keyword">else</span>&#123;<br>				<span class="hljs-type">char</span> t = stk_op.<span class="hljs-built_in">top</span>();<br>				<span class="hljs-keyword">if</span>(t == <span class="hljs-string">&#x27;(&#x27;</span>)&#123;<br>					stk_op.<span class="hljs-built_in">push</span>(c);<br>				&#125;<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(mp[c]&gt;mp[t])&#123;<br>					stk_op.<span class="hljs-built_in">push</span>(c);<br>				&#125;<span class="hljs-keyword">else</span>&#123;<br>					<span class="hljs-keyword">while</span>(t!=<span class="hljs-string">&#x27;(&#x27;</span>&amp;&amp;mp[t]&gt;=mp[c])&#123;<br>						<span class="hljs-comment">//取出操作数，先取出来的是右操作数  </span><br>						b = stk_num.<span class="hljs-built_in">top</span>();<br>						stk_num.<span class="hljs-built_in">pop</span>();<br>						a = stk_num.<span class="hljs-built_in">top</span>();<br>						stk_num.<span class="hljs-built_in">pop</span>();<br>						<span class="hljs-comment">//取出运算符</span><br>						op = stk_op.<span class="hljs-built_in">top</span>();<br>						stk_op.<span class="hljs-built_in">pop</span>();<br>						<span class="hljs-comment">//运算</span><br>						res = <span class="hljs-built_in">f</span>(a,b,op);<br>						<span class="hljs-comment">//结果入栈 </span><br>						stk_num.<span class="hljs-built_in">push</span>(res); <br>						<span class="hljs-keyword">if</span>(stk_op.<span class="hljs-built_in">empty</span>())&#123;<br>							<span class="hljs-keyword">break</span>;<br>						&#125;<span class="hljs-keyword">else</span>&#123;<br>							t = stk_op.<span class="hljs-built_in">top</span>();<br>						&#125;<br>					&#125;<br>					stk_op.<span class="hljs-built_in">push</span>(c);<br>				&#125;<br>			&#125;<br>			i++; <br>		&#125;<br>	&#125; <br>	<span class="hljs-keyword">while</span>(!stk_op.<span class="hljs-built_in">empty</span>())&#123;<br>		<span class="hljs-comment">//取出操作数，先取出来的是右操作数  </span><br>		b = stk_num.<span class="hljs-built_in">top</span>();<br>		stk_num.<span class="hljs-built_in">pop</span>();<br>		a = stk_num.<span class="hljs-built_in">top</span>();<br>		stk_num.<span class="hljs-built_in">pop</span>();<br>		<span class="hljs-comment">//取出运算符</span><br>		op = stk_op.<span class="hljs-built_in">top</span>();<br>		stk_op.<span class="hljs-built_in">pop</span>();<br>		<span class="hljs-comment">//运算</span><br>		res = <span class="hljs-built_in">f</span>(a,b,op);<br>		<span class="hljs-comment">//结果入栈 </span><br>		stk_num.<span class="hljs-built_in">push</span>(res); <br>	&#125;<br>	<span class="hljs-keyword">return</span> stk_num.<span class="hljs-built_in">top</span>();<br>&#125;<br><br><span class="hljs-function"><span class="hljs-type">int</span> <span class="hljs-title">main</span><span class="hljs-params">()</span></span>&#123;<br>	string s;<br>	<span class="hljs-built_in">getline</span>(cin,s);<br>	<span class="hljs-type">int</span> res = <span class="hljs-built_in">calculate</span>(s);<br>	cout&lt;&lt;res;<br>&#125; <br><br><br></code></pre></td></tr></table></figure>






                
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